A guide wire is used to facilitate insertion of a catheter into a lumen (such as digestive tract and blood vessel) of a living body. It leads a catheter slipped thereon to a desired position in a lumen.
A guide wire is also used to lead a catheter to a desired position in a lumen of a living body through an endoscope or a lumen of an endoscope at the time of observation or treatment of a lumen of a living body.
A guide wire for this purpose has a marker on its surface which tells its position and movement during insertion. A guide wire in a single color without a marker cannot be recognized for its movement when it turns around its axis. There have been proposed several methods for attaching a marker to a guide wire.
One method is described in U.S. Pat. No. 5,379,779 and involves slipping a hollow tube of polytetrafluoroethylene (PTFE), having one or more colored spiral pattern, onto a core wire and subsequently allowing it to be heat-shrink around the core wire of a guide wire.
Another method described in U.S. Pat. No. 6,811,958 involves adding a color producing agent (such as mica which produces a color upon irradiation with a laser beam) to the covering layer on the core of the guide wire and irradiating the covering layer with a laser beam for color development, thereby forming a marker as desired.
The above-mentioned guide wires include those which have surface irregularities formed thereon.
An example is disclosed in U.S. Patent Application Publication No. 2006/116609 in which the guide wire has a curved part on which surface irregularities are formed so as to make it more flexible. This guide wire has its surface irregularities formed from the outermost layer which is partly removed by heating a coil wound around the curved part at prescribed intervals.